What Can Whale Falls Teach Us About Life in the Deep Ocean?

POV Travel
Jul 24
8 min read

Somewhere between 1900 and the middle of the twentieth century, industrial whaling removed most of the great whales from the ocean. We know roughly what that did at the surface. We have the numbers, the ruined populations, the species pushed to the edge.

Nobody thought to ask what it did two miles down.

When a whale dies, it sinks. Its body descends for a mile, sometimes more, through the sunlit water, then the twilight, then the permanent black, and settles on the abyssal plain. And there, in what we describe as a desert, it feeds an entire world. Creatures arrive that live nowhere else. Bones sprout what look like red flowers. For decades, one carcass sustains a community of animals so specialised that many of them cannot easily live any other way.

We call this a whale fall. We only worked out that it existed in the last few decades.

Which raises a question we would rather you asked yourself than had us answer. If whaling removed most of the carcasses, what happened to the creatures that depended on them, in an ecosystem we had not yet discovered?

What can whale falls teach us about life in the deep ocean?

Quick Answer

A whale fall is the carcass of a whale on the deep sea floor, and it creates an oasis of life in an environment that is otherwise close to starving.

They teach us that the deep ocean is not empty. They sustain specialised creatures, including animals with no mouth and no gut that live on bone. They may act as stepping stones allowing life to move between isolated deep sea habitats.

And they teach us something harder. We reshaped a world we had never seen. Species may have been lost to whaling that no human ever recorded, in an ecosystem nobody knew was there.

A desert built on falling corpses

Almost all life on this planet runs on sunlight. Plants and plankton capture it, everything else eats them or eats each other, and the chain runs back to a star.

Sunlight does not reach the deep sea. Below a few hundred metres there is nothing to photosynthesise. The abyssal plain, which covers most of the surface of the Earth, is fed only by what drifts down from above: a perpetual thin drizzle of dead plankton and scraps, called marine snow. It is food. It is very little food, spread across an unimaginable expanse of mud.

So the deep is described as a desert, and in terms of energy that is fair. The animals there are sparse, slow, and adapted to hunger as a permanent condition.

Now consider what a whale represents. Tens of tonnes of oil rich tissue, arriving at once, in one place. It is not a meal. It is the equivalent of centuries of marine snow delivered in an afternoon.

And life was waiting for it. Which is itself the first strange fact. Waiting implies this has been happening long enough for evolution to have shaped animals around it.

The three feasts

Scientists have watched whale falls, some found by chance, some created deliberately by sinking stranded carcasses to study them. What follows arrives in sequence.

First the scavengers, and quickly. Sleeper sharks, hagfish, rat tails, swarming amphipods. They strip the soft tissue with astonishing speed, taking most of the flesh from a large whale within months or a few years. Watched from a submersible, it is not serene. It is a frenzy in slow motion, in the dark, thousands of metres down.

Then, once the obvious meat is gone, a second community works the bones and the enriched sediment around them. Worms, molluscs, crustaceans, picking through what remains, colonising the skeleton, feeding on the organic material soaked into the mud beneath.

Then the third stage, which is the one that should stop you. Whale bones are extraordinarily rich in fat. As bacteria break them down they release chemicals, including hydrogen sulphide, and around that chemistry a whole ecosystem assembles that does not eat the whale at all. It lives on chemical energy, harvested by bacteria, which feed everything else.

That stage can persist for decades on a single skeleton. The whale stopped living in one afternoon. Its body goes on working for half a century.

The animal with no mouth

Among the creatures that make a living here, one deserves your attention, because it is genuinely absurd.

There is a worm that has no mouth, no stomach and no gut. It cannot eat, in any sense you would recognise. It anchors itself to whale bone and sends root like structures burrowing into it. Inside those roots live bacteria, which break down the fats in the bone and feed the worm from the inside. The animal has outsourced digestion entirely.

The females sprout feathery plumes into the water, so a colonised bone appears carpeted in a strange red garden. In some species the males are microscopic and live inside the female's body, in numbers, reduced to little more than a supply of sperm.

Read that again and let it be as strange as it is. This creature lives inside another creature which lives inside the bone of a dead whale on the floor of the ocean. It is not a freak. It is common and successful, and it appears to have been eating whale bone for a very long time.

Life did not merely tolerate sinking whales. It built itself around them.

Stepping stones in the dark

Here the whale fall stops being a curiosity and becomes important.

Scattered across the sea floor are other rich, isolated habitats. Hydrothermal vents, where superheated mineral water pours from the crust. Cold seeps, where chemicals leak from sediment. Both support communities living on chemical energy rather than sunlight. Both are islands of abundance in a barren plain.

But islands they are. Vents open and close over decades, separated by vast stretches of nothing. So how does the life of one vent ever reach another?

Whale falls may be part of the answer. A decomposing whale skeleton generates the same sulphide rich chemistry that vent creatures depend on. Some scientists have proposed that carcasses act as stepping stones, temporary way stations scattered across the abyss, letting chemical dependent creatures disperse from one refuge to the next across evolutionary time.

Not everyone accepts this. The overlap between vent communities and whale fall communities is real but partial, and how much traffic genuinely passes between them is still argued over. It is one of the better disputes in deep sea biology, and it is not finished.

But if it holds, then the deaths of whales have been quietly shaping where life can exist on the floor of the ocean for millions of years. The corpses were never endings. They were bridges.

What we destroyed without seeing it

Now the part we think is the reason to read this at all.

Before industrial whaling, whale falls would have been dramatically more frequent. Carcasses would have landed on the abyssal plain in numbers we can now only estimate, sustaining far more of these communities, spaced far more closely, offering far more stepping stones to the creatures that hop between them.

Then, within a century or two, the rain of carcasses thinned drastically. Populations of bone eating, sulphide loving, whale dependent creatures would have found their habitat becoming rare and scattered and separated by distances they could not cross.

It is entirely plausible that species went extinct in the deep sea because of whaling. Creatures we never discovered. In an ecosystem we did not know existed. Killed by an industry operating two miles above them, by people who could not have imagined they were doing it.

We cannot prove it. There is nothing left to find, because we were not looking. And that is precisely the point we would like you to take away.

The absence of observed harm is not the absence of harm. It is frequently just the absence of observers.

Hold that against every reassurance you have ever been given that some industrial activity is safe because no damage has been recorded. Deep sea mining is being proposed across exactly the habitats described in this article. Nobody has surveyed most of them. Nobody knows what lives there. We are once again in the position of being able to reshape a world before we have discovered it, and once again the argument for proceeding is that no harm has been demonstrated.

Death as an economy

Step back from the biology and something close to philosophy emerges, and it deserves to be said plainly.

In the deep ocean, death is not the opposite of life. It is the delivery mechanism for it. Every scrap of energy on the abyssal plain arrived because something above died and sank. Marine snow is a rain of the dead. The whale fall is simply the most spectacular instance of a universal rule down there.

A whale spends decades in the light, gathering the productivity of an entire ocean into its body. Then it dies, and carries all of that energy, in one enormous package, into a place that would otherwise never receive it. Its body becomes an island, a food supply, a chemical reactor, a habitat, a bridge.

There is no waste in this system. Only transfer. A whale does not finish when it dies. It changes what it is doing, and goes on doing it for fifty years, in the dark, for animals it never met.

How POV Travel sees whale falls

We will never take you to a whale fall. Almost nobody has seen one. They are found by submersible, at depths a handful of humans in history have reached.

We tell you about them because of what they do to the water you are floating in.

When you are above the blue at Aliwal Shoal, or watching a whale sound and vanish beneath the boat off the South African coast, the ocean beneath you is not empty space. It is a working system, running top to bottom, and the animal you are watching will one day descend into it and feed a world you will never see, for longer than you will be alive.

That is what changes. The ocean stops being a surface with mysteries underneath and becomes one connected thing. It makes the living whale more significant, not less.

We question. We teach. We leave you with an opinion of your own.

And the question we would leave with you is not about whales. It is this. We discovered these ecosystems only recently, and we may already have damaged them beyond recovery without ever having seen them. What are we doing right now, to places we have not yet found, that the next generation will read about and wonder how we could possibly have thought it was safe?

Frequently Asked Questions

What is a whale fall?

The carcass of a whale that has sunk to the deep sea floor, creating a rich habitat for specialised deep sea creatures, sometimes for decades.

How long does a whale fall last?

Soft tissue is stripped within months or a few years. The skeleton can support life for decades as bacteria break down the fats in the bone and sustain a chemical based ecosystem around it.

What lives on a whale fall?

Scavengers such as hagfish, sleeper sharks and amphipods arrive first, then worms, molluscs and crustaceans. Later stages include bone eating worms that have no mouth or gut and rely on bacteria living inside them.

Why do whale falls matter?

The deep sea receives very little food. A whale carcass delivers an enormous amount of energy at once, and may act as a stepping stone allowing life to move between isolated deep sea habitats such as hydrothermal vents.

Did whaling damage the deep sea?

Very probably. Industrial whaling drastically reduced the number of carcasses reaching the sea floor. Species dependent on whale falls may have declined or been lost entirely, in an ecosystem we had not yet discovered.

See the ocean for yourself, top to bottom

You can read the science, or you can feel your heart rate settle as a mako slows to inspect you off Cabo San Lucas and then vanishes into the blue. These are not cage dives or baited spectacles. They are genuine encounters, in small groups, in wild water shared with animals that have ruled the ocean for hundreds of millions of years. It changes how you see them for good.

Explore the expeditions: Swim With Sharks & Marine Life →